A compact keypad for a telephone, PDA, remote controller, or similar device typically has between twelve and twenty keys for controlling the operation of the device. The keys generally include: number keys “0”–“9”; telephony keys “*” and “#”; and keys for additional functions such as “menu”, “cancel”, “cursor up”, “cursor down,” “cursor right,” “cursor left,” and “select”. In at least some instances, the device's size impacts the number of keys that can be conveniently accessed.
In order to increase the number of functions available through a device (or maintain a constant number of functions in light of decreasing device size), often several keys in the compact keypad are associated with multiple functions and/or meanings in order to enable the increased number of features and functions of the device. Commonly, the compact keypad functions as an alphanumeric keypad for features such as messaging and phonebook, where both letters and numbers are entered from the keypad.
Various approaches have been used to associate a single key with multiple alphanumeric characters. In one type of approach, a single key is associated with a single switch, and at least one key press (but usually more than one keypress) is required for the user to obtain the desired character. For example, a user presses a single key multiple times to cycle through alphanumeric choices until a pause (or pressing of another key) by the user indicates a selection of the currently presented character.
In a second type of approach, more than one switch is associated with a single key. Sometimes these multi-switch keys are referred to as “cluster” keys or “combination” keys. Near-simultaneous activation of one or more switches associated with the multi-switch key indicates which alphanumeric character is desired. This second type of approach is less cumbersome for alphanumeric character entry, because a user can manipulate a single key to access multiple characters directly. A user, however, is also more prone to make entry errors because the depression of the key must be precise enough to access only the desired switches and also because the tactile feedback for a multi-switch key is unfamiliar. For example, most users release a key after a single popple dome of a switch has been depressed, which is sometimes before the correct combination of popple dome switches has been activated to obtain the desired result in a multi-switch key. This user habit results in a need for changing the incorrect character entered and may eventually result in user frustration.
Thus, there is a desire for a compact keypad that facilitates direct alphanumeric character entry and entry of other functions. It is desirable that the compact keypad does not have an unusual tactile sensation. The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.